[67232] in North American Network Operators' Group
Re: MTUs - Was: Strange public traceroutes return private RFC1918
daemon@ATHENA.MIT.EDU (Laurence F. Sheldon, Jr.)
Thu Feb 5 15:51:15 2004
Date: Thu, 05 Feb 2004 14:43:39 -0600
From: "Laurence F. Sheldon, Jr." <larrysheldon@cox.net>
To: nanog@merit.edu
Errors-To: owner-nanog-outgoing@merit.edu
Warren Kumari wrote:
>
> Ok, I know that this is getting away from the original thread, but I've
> always wondered this...
>
> Why is the MTU on Ethernet 1500 bytes? I have looked through various
> docs (eg IEEE Std 802.x) and can find where maxUntaggedFrameSize is
> listed as 1518 octets, but there is no mention of why this was chosen.
> I know where the minimum frame size comes from (CSMA/CD and propagation
> times, etc), but the maximum frame size number sounds fairly arbitrary.
Because that was a conveniently large amount of very pricey memory
availble at the time?
Because that was the amount that could be blatted down a 500 meter
hose and get the "CD" part to work at some common clock rate?
